ABSTRACT
Chronic nonhealing wounds, such as venous ulcers (VUs), are a widespread and serious medical problem with high morbidity and mortality. The molecular pathology of VUs remains poorly understood, impeding the development of effective treatment strategies. Using mRNA expression profiling of VUs biopsies and computational analysis, we identified a candidate set of microRNAs with lowered target gene expression. Among these candidates, miR-16, -20a, -21, -106a -130a, and -203 were confirmed to be aberrantly overexpressed in a cohort study of 10 VU patients by quantitative PCR and in situ hybridizations. These microRNAs were predicted to target multiple genes important for wound healing, including early growth response factor 3, vinculin, and leptin receptor (LepR). Overexpression of the top up-regulated miRNAs, miR-21 and miR-130a, in primary human keratinocytes down-regulated expression of the endogenous LepR and early growth response factor 3. The luciferase reporter assay verified LepR as a direct target for miR-21 and miR-130a. Both miR-21 and miR-130a delayed epithelialization in an acute human skin wound model. Furthermore, in vivo overexpression of miR-21 inhibited epithelialization and granulation tissue formation in a rat wound model. Our results identify a novel mechanism in which overexpression of specific set of microRNAs inhibits wound healing, resulting in new potential molecular markers and targets for therapeutic intervention.
Subject(s)
Gene Expression Regulation , MicroRNAs/biosynthesis , Skin/injuries , Skin/metabolism , Wound Healing/physiology , Adult , Aged , Aged, 80 and over , Animals , Chickens , Disease Models, Animal , Dogs , Early Growth Response Protein 1/genetics , Early Growth Response Protein 1/metabolism , Female , Humans , Male , Mice , MicroRNAs/genetics , Middle Aged , Rats , Rats, Long-Evans , Receptors, Leptin/genetics , Receptors, Leptin/metabolism , Skin/pathology , TranscriptomeABSTRACT
A critical question in the treatment of chronic wounds is whether and when debridement is needed. The three most common chronic wounds are the diabetic foot ulcer (DFU), the venous leg ulcer, and the pressure or decubitus ulcer. Surgical debridement, aimed at removing necrotic, devitalized wound bed and wound edge tissue that inhibits healing, is a longstanding standard of care for the treatment of chronic, nonhealing wounds. Debridement encourages healing by converting a chronic nonhealing wound environment into a more responsive acute healing environment. While the rationale for debridement seems logical, the evidence to support its use in enhancing healing is scarce. Currently, there is more evidence in the literature for debridement for DFUs than for venous ulcers and pressure ulcers; however, the studies on which clinicians have based their rationale for debridement in DFUs possess methodologic flaws, small sample sizes, and bias. Thus, further studies are needed to develop clinical evidence for its inclusion in treatment protocols for chronic wounds. Here, the authors review the scientific evidence for debridement of DFUs, the rationale for debridement of DFUs, and the insufficient data supporting debridement for venous ulcers and pressure ulcers.
